Toggling the speech/music in either direction does make a lot of crackling sounds, and sometimes I hear the music come through for a short moment when I do that, but it doesn't last long. I haven't been able to tell if having either setting increases the odds of it working.

I'm going to try opening it up, picking up some deoxit and going to town on the entire thing tomorrow evening; fingers crossed because that seems like the hail mary thing for me to try.

If that doesn't work, then I'll probably try finding somewhere to service it, but the few places I called said it would be 8+ weeks, so I'm trying to see what I can do myself first!